我目前正在学习 SDL，并且正在尝试创建 Pacman 游戏。我正在尝试逐步进行，以免陷入大量代码的困境。
到目前为止，我已经创建了一个空白窗口并在上面渲染了一个 Pacman 图像。我可以按箭头键并在窗口周围移动 Pacman。我已经设置好了，所以 Pacman 图像存储为 SDL_Texture，我使用 RenderCopy 将其传送到窗口。每次用户按下箭头时，我都会移动图像的坐标并重新渲染整个图像。这工作得很好。然而，现在我想在屏幕上放一些点，让吃豆人吃东西。但是，如果我加载一个点图像并将其存储为新纹理以与 Pacman 一起在屏幕上闪烁，那么每次我移动 Pacman 时，点都会闪烁进出，因为它正在与 Pacman 一起被擦除和重新渲染。
我的问题是，如何避免这种“闪烁”？我可以以某种方式只重新渲染 Pacman 而不重新渲染屏幕的其余部分吗？还是有其他方法可以做到这一点？我想当我稍后在后台尝试创建迷宫时，我也会遇到同样的问题。如何制作每次重新渲染时都不会闪烁的静态背景？
以下是我到目前为止的代码。如果那里有任何格式错误的代码，请原谅我。正如我所说，我刚刚开始学习 SDL（对 C++ 也很陌生），所以如果有任何明显的“你不应该那样做！” 里面有一些东西，我会很感激有人指出:)
#include <iostream>
#include <SDL2/SDL.h>
using namespace std;
const int WINDOW_HEIGHT = 480;
const int WINDOW_WIDTH = 640;
const int MOVE_WIDTH = 10;
int main(int argc, const char * argv[])
{
SDL_Window* mainWindow = NULL; //To hold the main window
SDL_Renderer* renderer = NULL; //To hold the renderer
SDL_Rect targetRect; //Rectangle to which pacman image will be drawn
SDL_Surface* bmpSurface = NULL; //To hold bmp image
SDL_Texture* bmpTexture = NULL; //To hold bmp image
//Initialize SDL and check for errors
if ( SDL_Init(SDL_INIT_EVERYTHING) != 0 )
{
cout << "ERROR: could not initialize SDL." << endl;
}
//Create a window
mainWindow = SDL_CreateWindow("BAM", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, WINDOW_WIDTH, WINDOW_HEIGHT, 0);
if (mainWindow == NULL)
{
cout << "ERROR: could not initialize mainWindow." << endl;
}
//Initialize renderer
renderer = SDL_CreateRenderer(mainWindow, -1, SDL_RENDERER_ACCELERATED);
//Load image and store in an SDL_Surface
bmpSurface = SDL_LoadBMP("/Users/billgrenard/Desktop/Programs/SDL/SDL_KeyPresses/SDL_KeyPresses/pacman_closed.bmp");
if ( bmpSurface == NULL )
{
cout << "ERROR: could not load bmp file." << endl;
}
//Convert surface to texture for rendering
bmpTexture = SDL_CreateTextureFromSurface(renderer, bmpSurface);
if ( bmpTexture == NULL )
{
cout << "ERROR: could not convert bmp surface." << endl;
}
SDL_FreeSurface(bmpSurface);
//Define rectangle where pacman image is to be blitted
targetRect.w = 30;
targetRect.h = 30;
targetRect.x = (WINDOW_WIDTH/2) - (targetRect.w/2);
targetRect.y = (WINDOW_HEIGHT/2) - (targetRect.h/2);
//Main game loop
while (1)
{
SDL_Event e;
if (SDL_PollEvent(&e))
{
//Quit when user x's out the window
if (e.type == SDL_QUIT)
{
break;
}
//If user presses a key enter switch statement
else if( e.type == SDL_KEYDOWN )
{
switch ( e.key.keysym.sym ) {
//If user presses up arrow and the resulting move is inside the window, then move the Pacman's position
case SDLK_UP:
if ( targetRect.y - MOVE_WIDTH > 0 )
{
targetRect.y -= MOVE_WIDTH;
}
break;
//If user presses down arrow and the resulting move is inside the window, then move the Pacman's position
case SDLK_DOWN:
if ( targetRect.y + MOVE_WIDTH < (WINDOW_HEIGHT - targetRect.w) )
{
targetRect.y += MOVE_WIDTH;
}
break;
//If user presses right arrow and the resulting move is inside the window, then move the Pacman's position
case SDLK_RIGHT:
if ( targetRect.x + MOVE_WIDTH < (WINDOW_WIDTH - targetRect.w) )
{
targetRect.x += MOVE_WIDTH;
}
break;
//If user presses left arrow and the resulting move is inside the window, then move the Pacman's position
case SDLK_LEFT:
if ( targetRect.x - MOVE_WIDTH > 0 )
{
targetRect.x -= MOVE_WIDTH;
}
break;
default:
break;
}
}
}
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, bmpTexture, NULL, &targetRect);
SDL_RenderPresent(renderer);
}
SDL_DestroyWindow(mainWindow);
SDL_DestroyTexture(bmpTexture);
SDL_DestroyRenderer(renderer);
SDL_Quit();
return 0;
}
编辑：在回答 raser 的评论时，这里是我找到 PollEvent 示例的链接：http ://wiki.libsdl.org/SDL_CreateRenderer?highlight=%28%5CbCategoryAPI%5Cb%29%7C%28SDLFunctionTemplate%29